Crown Boiler Leaking Out Pressure Relief?

I've got a Crown boiler approximately 6 years old and it's pushing water out the pressure relief valve (I guess that is what it's called). Right after the boiler shuts off the gauge reads 180* and right around 30 psi. The relief valve says it's 30 psi rated so I'm not sure if the valve is a little weak or if something else is causing the leak. High limit is set at 170* and low limit is set at 150*. Any ideas? Thanks.

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Ok, I read through that. It doesn't sound exactly like what I've got. My expansion tank only has a schrader type valve at the bottom and I have no air bleeds at my radiators. I've just got regular baseboard type radiators. The pictures I attached will show what I've got. The picture of the gauge is right after the burner kicked off. At about 22-25 psi on the gauge water will start coming out the pressure relief.

first let the boiler cool down < 100F, then shut off incoming water, drain off water until pressure is at 0psi. check with tire gauge the pressure in the exp tank. should be at 12psi. if water comes out of shrader valve, then you need a new exp tank. if not at 12psi then use bike pump to get to 12 psi. open incoming water valve and watch gauge on boiler should not go much over 12psi. if above 20psi and rising then you need to replace the pressure reducing valve and at the same time i would look at replacing the backflow preventer. I really believe these could be DIY projects, but getting all the air out of the system can be a pain with out bleeders.

A few things you should know even if you get your pressure to below 30 psi your relief valve may still drip because normally they sit unused stuff in your water builds up then when it goes back down it may not seal fully and could drip. Also turning off the feed valve is a very bad idea, if it was broken the relief valve would be going all the time not just when it gets to temp.

I believe the warranty on an expansion tank is like 12-18 months they will die over the years it happens to all of us. On the bottem if your tank there is a black cap take it off and put your gauge on there. If it drips water it's dead, if you get air then there is hope, when If you have to replace it when you do I suggest you pick up a 1/2" ball valve (Iron Pipe IP) threaded and two nipples the idea is you can put an isolation valve on your tank to service it easier next time.

Well I let the system cool to right around 100*. Then I turned off water supply, then relieved the pressure with the pressure relief valve until the gauge read 0 psi. Then I checked the pressure at the bottom of the expansion tank with my tire gauge, the reading I got was 0 psi and some water dripped out of the shrader valve in the process.

As per Adam "I believe the warranty on an expansion tank is like 12-18 months they will die over the years it happens to all of us. On the bottom if your tank there is a black cap take it off and put your gauge on there. If it drips water it's dead, if you get air then there is hope, when If you have to replace it when you do I suggest you pick up a 1/2" ball valve (Iron Pipe IP) threaded and two nipples the idea is you can put an isolation valve on your tank to service it easier next time.

Yeah that is what I figured Yuri. I just wanted to post up the results. Is that expansion tank something I can replace or am I going to have a nightmare trying to bleed the air out of it? I checked out the manual that Adam posted the link to and it says something about running the water tap to bleed water. I know that is for a hot water heater, so I'm not sure how I'd bleed the air out of the heating system. Open a valve at the return manifold then turn up the thermostat for that zone until it circulates some water through? Would I have to do that for all 3 of my zones?